            \begin{tikzpicture}
            %------------------------------------------------------------------------------------
            \centering
            \begin{scope}[sibling distance=25pt, level distance=25pt] 
            \Tree[.\node(a1){:=};
                 	[.\node(b1){b};]
                 	[.\node(b2){+};
                            [.\node(c1){a};]  
                            [.\node(c2){*};
                                [.\node(d1){2};]
                                [.\node(d2){5};]
                            ]
                        ]
                 ]
            \end{scope}
            \begin{scope}[xshift=0em,yshift=-13em,sibling distance=30pt, level distance=30pt]
            \Tree[.\node(a1_){:=};
                 	[.\node(b1_){b};]
                 	[.\node(b2_){+};
                            [.\node(c1_){a};]  
                            [.\node(c2_){\color{red}{10}};]
                        ]
                 ]
            \end{scope}
            
             % \node at ([xshift=-10em,yshift=0.5em]SYNBL.north){符号表}; {\color{black}{var a,b:integer;}}
            \node (a) at ([xshift=18em,yshift=-1em]a1.west){(1)(* \quad 2 \quad 5 \quad $t_1$)};
            \node (b) at ([xshift=0.7em,yshift=-2em]a.south) {(2)(+ \quad a \quad \quad \quad \quad $t_2$)};
            \node (b1_1) at ([xshift=2em,yshift=-2em]a.south) {t1};
            \node (c) at ([xshift=-0.5em,yshift=-2em]b.south) {(3)(:= \quad $t_2$ \quad \_ \quad b)};
            
            \node (d) at ([xshift=0.5em,yshift=-6em]c.south){(1)(+ \quad a \quad \quad \quad \quad {$t_2$})};
            \node (d1_1) at ([xshift=1.5em,yshift=-6em]c.south){\color{red}{10}};
            \node (e) at ([xshift=-0.5em,yshift=-2em]d.south){(2)(:= \quad $t_2$ \quad \_ \quad b)};
            % \draw[blue!60, -{Triangle[width = 18pt, length = 8pt]}, line width = 10pt] ([xshift=2em,yshift=-5em]VALL.east) -- ([xshift=2em,yshift=5em]VALL.east);
            \draw[yellow!60, -{Triangle[width = 18pt, length = 8pt]}, line width = 10pt] ([xshift=-0.5em,yshift=-2.5em]c1.south) -- ([xshift=0em,yshift=0.5em]a1_.north);
            \draw[yellow!60, -{Triangle[width = 18pt, length = 8pt]}, line width = 10pt] ([xshift=-0.5em,yshift=-0.2em]c.south) -- ([xshift=-1em,yshift=0.5em]d.north);
            \node [draw=black,rectangle,inner sep=2pt,rounded corners=4pt,dashed,line width=1.0pt] [fit = (c2)(d1)(d2)] (box1) {};
            \node [draw=black,rectangle,inner sep=2pt,rounded corners=4pt,dashed,line width=1.0pt] [fit = (a)] (box2) {};
            \node [draw=black,rectangle,inner sep=2pt,rounded corners=4pt,dashed,line width=1.0pt] [fit = (c2_)] (box3) {};
            \node [draw=black,rectangle,inner sep=2pt,rounded corners=4pt,dashed,line width=1.0pt] [fit = (b1_1)] (box4) {};
            \node [draw=black,rectangle,inner sep=2pt,rounded corners=4pt,dashed,line width=1.0pt] [fit = (d1_1)] (box5) {};
            \draw[->,black,very thick,dashed] ([xshift=0.7em,yshift=0em]box2.south) -- ([xshift=-0.9em,yshift=0em]box5.north);
            \draw[->,black,very thick,dashed] ([xshift=0em,yshift=0em]box1.south) -- ([xshift=0.5em,yshift=0em]box3.north);
            % \node (e) at ([xshift=9.2em,yshift=-3em]a1.east){或};
            % \draw [->] (set a) to node [auto] {\textit{q}} (set b);
            
            % \begin{pgfonlayer}{background}
            % \node [fill=yellow!10,fit=(a) (b) (c)(b1_1)] {};
            % \end{pgfonlayer}
            
            % \begin{pgfonlayer}{background}
            % \node [fill=yellow!10,fit=(a1) (b1) (b2)(c1)(c2)(d1)(d2)] {};
            % \end{pgfonlayer}
            
            % \begin{pgfonlayer}{background}
            % \node [fill=purple!30,fit=(a1_) (b1_)(b2_) (c1_)(c2_)] {};
            % \end{pgfonlayer}
            
            % \begin{pgfonlayer}{background}
            % \node [fill=blue!10,fit=(d) (e)] {};
            % \end{pgfonlayer}


            %------------------------------------------------------------------------------------
            \end{tikzpicture}